Railway braking apparatus



Nov. 22, 1932.

H. L. BONE ET AL RAILWAY BRAKING APPARATUS original Filed May 12, 19:51'

Patented Nov. 22,' 1932 HERBERT L. BONE, or swrssvALn, AND JOHN w. LrvINGs'roN, or WILKINsBURe, rENN- y sYLvANrA, AssIGNoRs 'ro man UNION SWITCH a SIGNAL COMPANY, or swIssvALn, f PENNSYLVANIA, A coaroiaAfrroN or rLNNsYLvANrA l f v nALLvs/'mr BRAKrNG ArrAnA'rUsl i..

Application led May 12, V.1931,.Seria1 Our invention relates-to railway braking apparatus, and particularly to braking apparatus of the type comprising a braking bar The accompanying drawing is a View, partly diagrammatic, illustrating one formv of..

railway braking apparatus embodying our invention.

Referring to the drawing, the reference. characters 1 andla designate thetrack rails of a stretch of railway track. Located on opposite sides of rail .1, and extending parallel therewith, are two braking bars 2 and 3. Two similar braking bars 22L and 3a extend parallel with rail 1a on Vopposite sides thereof.

Thebraking bars 2, 3, 2% and 8a are operated by a fluid pressure motor M, which, in the form here shown, comprises a cylinder 4 containing an auxiliary piston 6 which is movable between the left-hand end of the cylinder and an intermediate point inthe cylinder, and a main piston 5 which is movable between retracted position at the righthand end of the ylinder and a projected position where it engages the auxiliary piston 6. It will .be plain, therefore, that when the auxiliary piston'G occupies its projected position, in which position it is illustrated in l the drawing, the strokeof lthe lmain piston 5 is less than when the auxiliary piston 6 occupies its retracted position. The sealing ring of the auxiliary piston 6 is located at 6ar in the drawing, and the parts areso proportioned that even when Athe auxiliarypiston occupies its projected position, it does not blank a'pipe 28 which communicates with the side of the cylinder Ll. .Piston .6 isprovided with iiutes orholes by means of which the pipe 28 may at all times communicate with the region between pistons 5 and 6. 'The mainpiston 5 of motor M is attached to a piston rod 7, which piston rod, in turn, is operatively connected with the brakingbars, 2, 3, 2 anc Sa by means of suitable operating No. 536359,' nieuwe@ .may 4, 1932.

describe.`

,As here shown, this operating mechanism comprises a link 8 which is connected at one end to thefree end of the piston .rod 7 and .l

at the other end to one arm `of a three-arm lever 9 whichis pivotally supported-in the trackwayat 10. -jThe second arm of: the lever 9 is connected, through a link 11, with a crank 12y which is pivotallysupported lin the trackway. at 13; and 'thethirdgarm of lever 9,'v is connected,ilthrough a link"'1:4;,`with"a crank 15 which is pivotallyisupported in the trackway at 16; It will beseen,r `therefore, that the links 1l andjllland thelever 9l constitute `a toggle by means of which the cranks'12 and 15 may be swungin'the same directions when the main piston 5 of motor M is operated.

' The free end of crank 12' is operatively connected withthe braking bars 2 and 2, respectively, by means of resilient connections which include springs 17 and 18; and, similarly, the freeend of the crank 15 is operatively connected with'V the braking bars 3 andv 3a by means of resilient connections which 'include springs 19 and 20.' It will be seen, therefore, that when piston 5 moves toward the left', the cranks 12`and 15 lare both swung in a clockwise direction, so that each braking bar is movedtoward the associated rail into a braking position in vwhich it engages the mechanism,f.one formof which we will now sides of alwheel of a railwaycar traversing the rails 1 and laf yWhen thepistoni moves toward the right, however, the cranksV 12 and 15 are both swung in counter-clockwise direction, and the braking bars are moved away from the associatedrailsto their non-brak-V ing positions, in which they areout of engage'- ment with the wheels of a passing car. form of operating mechanism of the type de"- scribed is disclosed rand claimed in `aco-pending application for Letters, Patent of the One United States, Serial No. 307,895, tiled by `Herbert L. Bone on Sept; waybraking apparatus. The motor M is controlled by. four magnet 24, 1928, I'for railvalves V1, V2, V3 and Vf. `As hereshown,

each valve V comprises avalvestem 21,-biased to an upper position by a spring 22, and provided withan armature V23 and a winding 24.

When valve V1 is energized, valvestem 21 of this valve moves downwardly against the bias exerted by spring 22, as shown in the drawing, and a pipe 26, which communicates with the left hand end of cylinder 4, is then connected'with a pipe 25 which is constantly supplied with fluid pressure, usually air, from a suitable source not shown in the drawing.

When valve V1L is deenergized, howevervalve v stem 21 is moved upwardly by spring 22, and pipe 26 is then disconnected from pipe 25. When valve V2 is energized,valve stem 21 of this valve moves downwardly, thereby connecting pipe 26 with-pipe 28, but when valve V2 is deenergized, pipe 26 is disconnected f from pipe 28. -When valve V3 is energized, va `pipe 29 which communicates with right hand endk of cylinder 4, is vented'to atmosphere through a port 27 5. butwhen valve V3 is deenergized, pipe 29 is disconnected from atmosphere, and pipe28, which is disconnectedfrom port27 when this valve is energized,

ringto the pressure responsive device P30, for` example, this device comprises a Bourdon tube 44 connected by means of a pipe 3l with pipe 28, and so subjected at all times to the pressure in the middle of cylinder 4. The vBourdon tube 44 controls a contact 45--'-45al rwhich is closedat all times except when the f pressure exceeds a predetermined value which is just suiiicientto move the braking apparatus to its open position. LFor eXam ple, this. pressuremight be thirty pounds per square inch. The pressure responsive devices P10 and P40 are similar to the pressure responsive device P30, except that the Bour- ,don tubes 44 of these devices are connected to a pipe 30 which enters cylinder 4 at such n' point that these tubes will be' subjected to the ypressure in the region between the pistons .5 and 6 until piston 5 has moved toward the left just far enough to move the braking barsk to their brakingpositions, after which these tubes will then be subjected` to they pressure in the region between the main'piston 5 and i the right-hand end of the cylinder.V That is "to say, devices P10 and P50 are responsive to Vthe pressure in front of piston 5 when the piston is in its retracted position, and to the pressure'behind the piston when the lat'- ter is'i'n its projected positions. The pressure responsive device P is likewise similar f to the pressure responsive device P30, but the Bourdon tubev 44 of this, latter vdevice is rconnected with apipe'32, which pipe' in turn, is connected with the interior of cylyhand end of the cylinder.

sponsive devices P10, P40 and P70 are ar- Y.

increased. below ten pounds per square inch, contact 45-45a of each of these devices is closed.

inder 4 at such point that this pipe will be blanked by piston 5 when and only when piston 5 occupies the position in which it engages the auxiliary piston 6 when the Yauxiliary piston 6 loccupies its projected position. It will be seen, therefore,'that when piston 5 occupies any position tothe vright of the position in which it engages the auxiliary piston 6 in the projected` position of the latter, Bourdon tube 44 of pressure reysponsive device P70' will be subjected Ato the pressure in the region of cylinder 4 between the pistons 5 and 6; but that when the piston 5 occupies any position to the left oi' such position,'the Bourdon tube 44. of the pressure responsive device P70 will then be'subjec'ted to the pressure in the region of cylinder 4 between the piston 5 and theV right- The pressure reranged to operate successively, asl the pressure to which these devices are subjected is For example, forv all pressures If the pressure exceeds ten pounds per square inch, however, Contact 45-450l of device P10 opens, andV if the ypressure'eizceeds twenty pounds per square inch,'contact 415-0450 of 4 'device P10 closes. 'In similar manner,`the pressure responsive' devices P40 and P70 are adjusted to open their contacts y45-.`45a at forty and seventy pounds per square inch, respectively, and to close 'their contacts 45-45b at fifty and eighty pounds per square inch. Of course, these specific pressures are not essential, butare only mentioned Vfor purposes of explanation'.

The valves V are further controlled by j means of a manuallyoperable lever L which, as here shown, is capable of assuming five positions, indicated by the' dotted lines in the drawing, and designated by the reference characters p0, p1, p2, p3 and p4. The lever -L controls a plurality of contacts 83-34,

35-36, 37-38, 353-40, 41-42, 43-46 and 43-47. Contacts 38-34 andV 43-46 yare closed when lever L. occupies its p0 position; contact 35-36 is closed when lever L occupies its p1 position; contact 87'-38 is closed when lever L occupies its p2 position, contact v394-40 is closed when lever Loccupies its p3 position, its p4 position, or any position intermediate these two; contact 41-42 is closed Awhen lever L occupies/its p1 position, its k00 position, or any position between these two positions; and contact 43-7-47 is closedwhe lever L occupies' its p* position.

The lever L will usually be located at [a point remote from the braking apparatus, 7...;

as in the controlv4 cabin of 'a'classiication yard car retarder system, and will be connected with the braking apparatus by means of line wires extending Vfrointhe control v cabin to the braking apparatus.

As shown in the drawing, lever L occupies its P0 0I' Off position.l A circuitisthereL g port 27.` With lever Lf in its vp0 position',a `circuit is 'also completedl forvalve V2 at contact 48x-46 oflever L, andi current Hows from battery B through line Wire 48, Winding 24 of valve V2, line Wirev 58, contact 43-'46 off lever L, and Wire 57 back to battery B. Valvev V2 is therefore also' ener-` gized, so that pipe 26 is connected With pipe 28. Furthermore, with lever L in its p0 position, if the pressure in the region of cylinder 4 between the pistons 5v and 6 is `below thirty pounds per square.inch,'a circuit Will also be completed for valve V1, which passes from battery B through line Wire 48, Winding 24 of valve V1, Wire 59, contact 45-45a of pressure responsive device P20, line Wire 52, Wire 53, Contact 33-34 of lever L, and Wires 54,55, 56 and 57 back to battery BQ Valve VV1 will therefore become` energized and will connect pipe 26 With pipe25. W hen pipe 26 becomes connected with pipe 25 under these' conditions, fluid pressure will bead- Initted to the left-hand end of the cylinder,

. and also to the rcgionbetvvcenthe pistons 5 and 6, untiljthe pressure in `these regions exceeds thirty pounds per squareinch, fat which time contact 45--45a of pressure responsivedcvice P20 Will open and Will de- `energize valve V1. Valve V4 is deenergized.

It will be seen, therefore, that `when lever L occupies its p0 position,l piston 5 of motor -Mis held vinfits extreme right-hand position in cylinder 4 by'a pressure of thirty pounds per square inch, and the braking bars there fore occupy their retracted or ineffective positions. Since piston 5 occupiesl its extreme right-handv` position, the Bourdon .tubes 44 of the pressure responsive devices P10, P

and P70 are subjected to the pressure in the region of cylinder`4 betweenthe pistons 5 and 6. Contact `4'5-450'of device P10,'con tact 45--45a of Vdevice P40, and contact r4545a of device P70 are'therefore all closed, -While contact 45'-`45 of device P10, contact 45-451 of device P40 and contact 45-4'5b of Y device P are all open.

In explaining the operation of the appara-y tus as a Whole, I will iirst assume that the operator Wishes to make a comparatively.

light brake application. .To do this, he moves lever L to its p1 position, thereby opening contacts 355-34 and 43-46 of lever'L and closing contacts 35'-36 and 4,1-42 of lever L. The opening of .contact 3S-34 interrupts the circuit previously traced for valve V2', and

the opening of contact 4.3-46 opens the ciry 28, thusdisconnecting the regionbetvveenithe pistons 5` and 6 from the left-hand end of cylinder v4. The lopenings ofcontact B3-34 of lever L also 'interrupts the circuit previously traced for valve V1. "i Itshouldbe noted that when pipe 28 become'sjconnected with atmosphere, the pressurein'thisfregion'ofv cylinder '4`betvveen pistons 5 Aanvdr6 rapidlyfdeQ Y p I 'creases to atmosphere pressure, so thatii` contact 45-45afof pressure responsivedevce P20 happens'to be gopenvvhen lever'. L is movedgto its p1 positiomthis contact -vvill almostinrfV f mediately become closed. Furthermore,due

to the decreased pressureI fin-fthe region -between thev pistons l5 andY 6,V contact 45-451- 'of pressure responsive 'device P10, which was previously closed, will become open, and contact 45"'-452L which Was previously open, Will 'i become closed. is soon as contacts 41;42 of lever L and contact 45-452 of `pressure responsive device P20 both become closed, ai cirn cuit is completed for valve-V1 'which Vpasses rorn` battery C throughivire 161', contact` 41-42' oflever L, Wire 60, linevvire 52,' c'o'ntact`45--45a of pressure responsive device P20, 'Winding 24 of valve V1, andflin'e Wire 48 baci;4 f to battery C. Valve V1l therefore becomes ico. i

energized, and admits'fluidaatfull line presy i sure to the lett-hand end ofthe .cylinder -t'o hold the Vauxiliary piston i6 in its projected position under these conditions. lilurthcrn more, as soonas contact 45-451of pressure responsive device P10` and contact 35i- 36 ofl lever'L both become closed, acircuitis completed for valve V4 Which passes from bat-v 1 .p

t'ery C through `Wires 6l and 62, contact`85e36 fof lever L, Wire 63, linevvire64,'1asymmetric unit 65 in its loiv'resistance direction, Wire 66, contact 45e-452 of pressure responsiverde- 4vice P10, Wires 67 and 68, windingf24of valve V4, and line Wire 48 baclr to battery C. Valve V1 therefore becomes energized and connects A c pipe 29 .with pipe 25, so that fluid 'pressurei's' noiv-suppliedto theright-hand end ofthe cylinder. This pressure drives A:piston 5 to- Ward the left, thereby movi-ng the brakingy commence the movementfof the braking bars maybe built'upl to full line pressure which may beof the order of one 'huiidred pounds iso 12o bars toward ,their braking Y* positions. f It, lshould benoted that the'lprefssure available/to I the braking` apparatus, BourdonA tubes 44.- of

the pressure responsive devicesLP andv P40 become subjected toy thefpressure inthe right hand end. of tl'iecylinder.` inasmuch as'this pressure under these" conditions is fullline pressure, thecontacts IE5-511 of these-de vices V`now becomeyop'enedfa-nd the contacts y -450 become closed. The opening of conof fluid pressure to the rightfhand end ofV cylinder 4. The closing'of contact 454-450 of pressure responsive device P10'comple`tes a circuit for valve V3',and current flows from battery C through wires 6l and62, contact ,S5-#36 of leverL, wire 63,1inewire 64, asymmetric unit .in its low resistance direction, wire 66, contact L t5-451 of pressure responsive device P10,1wi ,re49,-windin`g 24 of valve V3, and line wire48 back to battery C. vVtherefore becomes energized and connects pipe 29with port 27 so that the right-hand end of cylinder. iis then exhausted to atmosphere. This end of :the cylinder will, then continue to be exhausted to atmosphere until the pressure therein has been reduced below twenty pounds per square inch, whereupon contact l5-451 of vpressure responsive device P10will open and will deenergizefvalve V3. If the pressure in the right-hand end o f cylin- A-derwt now vdecreases vbelow ten pounds per squareinch fon any reason, Contact45e-4:5a

Aof pressureresponsive device P10 willagain become closed Aand will complete the circuit previously traced for valve V-f including this contact, soy thatvalve V4. will again become energized. Valve V4 will then remain energized until the pressure in the right-hand end ofthe cylinder exceeds ten pounds Vper square inch vatwhich time contact lf5--4f5a of pressure responsive device P10 will again open to deenergize this valve. It will be apparent, therefore, from the foregoing, that when `lever L occupies v its p1 position,`piston 5 is urgedv toward the left'by a pressure; of Ybetween tenand twenty pounds per square inch. The movement of piston 5 toward the left under these conditions islimited by the i auxiliary piston, which aspointed out hereinbefore, is held in its projected position by y,fluid at-full line pressure, and the parts are so1 proportioned Vthat the movement `of lever A9 caused by this movement of piston 5 Adoes y not bring the toggle of which lever 9 forms ythe operating mechanism to the piston 5. VVVAs a result, thepiston 5 maybe moved slightly to the right,therebycushioning the braking Valve action ofthe apparatus againstthevolume of y #m i 37-38 and 41--42 are closed. Tlieoperation of the apparatus is then similar to ythat just vdescribed with the, following exceptions.

Valve V4 is now initially* energized over a` circuit which includes contact 37-38 'oflever L ,and which passes from battery B through line wirelS, winding Zeef valve V4, wire 68, contact l5-45a of pressure responsive device P40, wire 69, asymmetric unit 7 O V'in Vits low resistance direction, 'linefwire64t," wire 71,

contact 37-38 of lever L, andwires', 56 and 57 back -to battery C. I When piston `5 has moved toward the leftto thegposition in which devices P10 and P40 become subjectedV to the pressure in the right-handfend of the cylinder, contact 4.5454 ofpressure respon-r sive device P40 will lopen and contact 'iwf-451" thereof will-becomeclosed. YThe Vopening of contact 45-fl5a of this Vpressure responsive device will interrupt the circuitvlast traced for valve V4 and so will deenergize this valve. rPhe closing of contact 15-450 of device-P40 under these conditions, will complete another circuit for valvev V3, and current will Aflow from battery B through line wire 48,.wind ing 24 of valve V3, ywires-49 and 72, contact 45-450 of device P40, wire 69,asymmetri`c 'unit 70 in its low resistance. direction, line wirel, wire 71,'contact`37f-88 of 4lever L, and wires 55, 56 and 57 back tobattferyy 1B.

Valve V3 `will therefore become vdeenergized and willvent fluid from theright-hand end of Acylinder l until the pressure "in this end' of the cylinder decreases below fifty pounds per square inch. Ifthe pressure in this end o f the lcylinder under ythese conditions de creases below forty pounds per square inch j Y for any reason, contact l5-454 of pressure V,responsive device P40'will again become closed andwill energizevalveVtto supply flui d-pres l sure to this end of the cylinderuntilthe pressure again exceeds forty pounds persquare inch. It willbe apparent,therefor'e that when lever L occupies its p2 position, the piston 5'is forced toward the left-hand'end'of cylinder 4:, and is held'against auxiliary pistonG, .by

fluid under a vpressu're'of between forty and fifty pounds per `square inch.

If the operator moves'lever `L to its?)3 posi.- Y 1 battery B through line' wire 48, winding 24 tion, acircuit is completed for Vvalve' VA from of valve V4, wires 68. and73, contact l5-45. ofl pressure responsive device lP10,'linewire 74, Contact 39-40 of lever L, and Wires 56 and 57 back to battery B. Valve V4 therefore becomes energized and admits fluid pressure to the right-hand end of cylinder l to moveV piston 5 toward the right in the mannerpreviyously-described. Under these conditions piston 6 is held in itsprojectedposition-by is interrupted andv valve V1 therefore becomes virtue )of the circuit l previously traced ,fort valve V1, including contact41-c-42 of leverl 4 n,

Y inch. It will be apparent,- therefore, that un-v -f derthese conditions, piston 5 is held'inits extreme left hand;position by ,a pressure of be!l L, so'that the movement of piston 5 isar'-,

rested when it engages the auxiliary piston 6.` lAs previously pointed out when piston 570ccuvplesthe position inwhich it engages they auxiliary piston `Geit blanks the pipe by means of which the Bourdon tubej44 of pressure responsivedevice P70 `communicates .with

cylinder 4, and it will be apparent, therefpre,V Y that under these conditions Contact 451-451` of pressure responsive devicePmremains closed so that valve VVremainsQenergized.-`

Piston `5 is therefore heldin the positionv in which it engages the auxiliary pistonfl'by fluidl at full line pressure.

If a is desirable to l apply afjsaii higherl braking force, the operator moves llever -L to its p4 position, thereby vopening contact.

y 2'0 41-(42 and closingrcontact 43-447. l When contact 41,-42 is opened,the circuit previously traced for' valve V1 including thiscontact deenergized, so that the supply of fluidl pres-A sure to the leftghand endl of cylinder 4 is cut t oil?. When contact 46-47 of lever Lbecomes closed, a circuit is completed 'for valve V? which is similar to thecircuitV previously traced for this valveexcept that this circuit instead of including the Contact 43-46 ofl lever L includes Contact .4S- 47 oflever L. Valve V2 therefore becomes energizedand since all circuits for valve V3 are( now open,

' so that valve V3 isdeenergized, the 'left-hand end of cylinder 4 is vented to atmosphere.

Furthermore, since contact 394- of lever Lis closed under these conditions, the circuit last traced for valve V4t is closed, 'and valve V4L thereforealso becomes energized; .Fluid at full line pressure is therefore admitted to the right-hand end of cylinder 4 in the man?A ner previouslydescribed, and, since ythe'fleftfk hand end of cylinder 4is vented to atmos# phere, `this pressuremovesthe pistons and 6 to the extreme left-handend of the*cylinder,v As soon as piston 5'Inoves-past theposition in whichk it engagesrthe auxiliary pistone in its'- projected positiompressure responsive device P70 becomes subjected tothe 'pressllre'yv inthe right-hand end of the cylinder. Inasmuch as this A pressure is full line pressure,` contact %45a of device P70 now becomes opened.l and contact 45-45b becomes closed. y The opening of contact 45-45a interrupts the circuit last traced for valve Viso that this valve becomes deenergized, Y while the closing of*V contact 45-45b-of pressure respqn'sv device P79 com?, pletes another circuit Vfor valve VVs which passesfrom battery AB through line -wire 48, winding 24 of valve Vjwires 49 and 72, con.` tact 45---45b i of pressurev responsive rdevice j P", linewire 74, contact`39-.4O of lever L, and wires and 57 back to battery B.` Valve V3 thereforebecomes energized and vents fluid Vromthe right-hand end ofeylinder 4 until the pressure in this'end of the `cylinder decreases below eighty pounds perfsquare tween seventy land eighty pounds per square inch., The parts are so proportionedzthat when piston 5 occupiesthis position, leverv9` occupies the position in which the togglev of which it forms a `part is nearly on dead-cemV the reactionof ordinary car wheelsis not sufiicient tomove the toggle mechanism and the entire forces exerted by the'spring's v17 ,918, i llQand 2070i the resilient'fconnections are e available toholdthe braking bars againstthe ter." When thefparts occupy these positions, [.j

wheelsof a car, l, however, when the parts enter the. braking apparatus, the additional? force 'exerted on thebraking bars by the .wide

voccupy these-positions, a locomotive 'should driving/wheels ofthehlocomotive will be sui-l i'cienttol move the toggle mechanism away It should be .observed that moves the'leverL from a position corresponding to .a higher braking force to a position corresponding to a lower brakingfforce, the apparatus will immediately and automjatical-lV ifithe'op'erator e i ly lreducethe brakingforceto Va valuecorref .f spending to vthev new position ofthe lever, for

reasons which "will lbe apparent fromv the drawing without tracing the operationszin detail.f

leo

In order t0 restore the apparatustromits closed or eiective position to itsnlopen or in;l Ve'l'ective position, the operator )moves lever L toits 'p0 position inw'hichitis illustrated in the drawing.4 The closing of contact S33- 84 of lever L under these .c'onditions'fcomv-l .Y pletes the-circuit previousl tracedforvalves` 43445 completes the circuit previously traced for valve V2. Valves V1, V2 and Vffthere-v fore now all become energized, The ener?A gization of valve .V iadmitslfluid pressure to energicdso *that .pipe 26 is Vsuppliedfwith vhiid Vpress'ure,"ui`d pressure then admitted to the region betweenthe pistonsl'and'l.

iis Y ing. `f Theenergizaton of` valve V2 connectsj pipe Q-withpipeQS, and since' valve.V V 1` is j Y Thefenergization of valve Vsfjdi'sconneet's f' p'ipezQSV fromv atmosphere and connects pipe l 29 with atmospheregfWhen pipe 29,*is` con-v,

l nected with atmosphere, the pressure in fthe right-hand @11d Y ef Cylinder his fvexjhausted,

and the pressure*between the pistons 5 andy 6V therefore moves. pistonf,Y toward the 2 right tok restore the braking vaplpzngatus toitsopten"v ,y

aaai in are" diawiiig; if the passerais the region of cylinder 4 between the pistonsv f'and 6 exceeds thirtyl pounds per square inch during the movement of lpiston 5 tc-fV ward the right, contact f-flaof pressure responsive device Psowill open as previously described'gy and will interrupt the circuitfor valve V1 including tliis'contact,V` Valve 4Vl` Will, therefore, become deenergized. and cut o f the'supply ofiluid pressure tothe'region between the auxiliarypiston Gand the adja- Y cent lend'- `of the cylinder, and between" the pistons 5` and After the pressurel has again dropped l.belovv thirtypounds per Y square inch, contactV fif-iof pressurefre'- sponsivevdevicefPgo; will again-become closed be seen, therefore, that piston 5' 'is moved to .y its right-hand positionandzis subsequently maintainedV in this position by a pressure' of( tliirtypeunds per square' inch.' Then the pistonreaches its riglitdiandposition, the

parts-'are restored vto/their normalv conditions iii'vvhich they 'are illustrated inY the drawing.

Although We have herein shown and described only `one form 'of railway braking apparatus embodying our invention, itis understood that various changes and ino'dilica-V tions may loe4 made therein Within the scope offthe appended claimsvwithout departing from the spirit and scope of our invention.' I 'Having thus described ourinvention, what Weclaim'isr.A l '7. l* (l. Trackway ear retardingapparatusrcom prising 'a'cyliiiden piston movable thereinlv Yand having ai retracted anda projected posi-A -tiormmeans for' normally admitting Huid pressure in front of said piston to `move it to its re- Y tracted positiom'means Yfor at times admitting' 40l Huid pressurebehind .sai-d piston to move it to itsl pro] ected: position, pressure `responsive means connected' ywith said cylinder at` such point vas tobejr` Asubjected to the pressure vin Y 'front of said y, piston when 'the y. piston? is' in". its retracted position to' the trolledby said pressure resp'ensive Vmeans for* deterniiningthe pressurebehind said piston Landcar retarding lmeans operate'dby said K piston.` Y

12. vlrackvvaycar retardingapparatus comprisniga cylinder, la pistonV movable therein and having va-retracted anda projected' posii tion, means'for at times moving said pisa tonl toits retracted position, vmeans for at other times admitting,fluid"pressurebehind said'pistonto moveit to its projected posi# tion, pressure responsive means connected vvith Vsaid cylinder at such pointastobecome subjectedfto the pressurefbehind said piston Qvvhen and 'only When said pistonhas been moved awayv from its retracted position more than aj predetermined distance, means coni trolledby said pressureresponsive imean'sffor i 'to its retracted "osi-tion' Vsaidpiston to move it to itsvprojected posi,-A Vtion,r ,pressure responsive 'means connected Y,

with said cylinder 'atsuch point as to'becoine subjected'to the pressure behind said piston whenv and-only when saidepistoii has` been than .a predetermined "distance, means Con-l trolled by said pressure responsive means and effective When saidl pressure meansbecomes subjected'to'the/pressure behind the pistonk for decreasingY this pressurea predetermined amount, and car 'retarding means operated by said piston. A i

4.* V'lraelway car retarding ,appzrir'atus comiprising a'cylinder, a piston movable therein and having aretractedvand a projectedlposition, means for at times moving said piston y to itsl yretracted position, means'ffor at other' timesadmitting fluid pressure behindsaid pistonto moveV it to its: projectedy position,

pressure respoiisive`ineans yconnected with said cylinder at such pointV asto become subi jectedto the pressure behind s aid'piston'when and only f'vvhen lsaid piston has'been moved away from its retracted position more than 4V a predetermined distance, means controlled by said pressure responsive means and effec tive when said pressurek mea-nsbecomes subfv Y j ected to the pressure behindl the piston for decreasing thisfvpressure to, and for subsequently maintaining it at, a vvalue Which-falls Within' predetermined limits', and'car retarding means :operated by :said piston:`

5i vT raclnvay carretarding apparatus comi i prisingV a cylinder, a 4pist'c'in'movable therein 'andv having' a retracted and la Aprojected position, means for at: times" movingr saidpiston Y y Womagnet vvalves, means v,c'oi'itr'olle by the; Q ne vvalvedor admit#` tingv'iluid pressure pistont'o move lit' to its `projected position, .means controlled liiol theother `Valve for exhausting fluid 'I sure frompbehind said piston, fpre'ssurejrei sponsive means connectedl with said cylin dery at such'. point astobe Ysubjected tothe pressure lbehind said piston When-'aridjonly When'saidfpiston has 'been moved'avvayfrom its retracted position' more than a predetermined. distance, means: controlled'by said pressure'responsive' means fon-controlling iiieans operated: lpiston. Y* f Traclgivay car ret-arding apparatus fconiprising` a cylinder, la piston movable-therein seidxtivo lmagnetvalves, aridcar Vretar'ding and havinga'r-etractedjand apr-ojec'ted'posit 'tion'ymeans forat Vtimes movingA saidfpist-o'n moved avvayfrom its retract-ed position l'more kSi? i to its retracted position, two magnet valves, means controlled by the one valve for admitting fluid Pressure behind said piston to move it to its projected position, means controlled by the othervalve for exhaustingV fluid pressure from behind said piston, a pressure rel sponsive device connected With said cylinder at such point as to be subjected to the pres-` sure behind said piston when and only When said piston has been inoved away from its retracted position more than a predetermined distance, a normally closed Contact controlled bysaid pressure responsive device rand ar-iy ranged to become opened it the pressure to which said pressure responsive device is subjected exceeds a predeterminedvalue, a normally open contact controlled byV said pres-y j sure responsive device and arranged to be-'r come` closed it the pressure to Which said pressure responsivel device is subjected eX- 4 ceeds a predetermined value `Which is somewhat higher than tne value at which said nor-` Y mally closed contact becomes opened, a circuit for said one valve controlled bysaid normally closed contact, a circuit for said other Y Venergizing said third magnet valve, and car yretardi'ng means cont-rolled bylsaid piston.

8,.` TrackWayV car retarding apparatus com? prising a cylinder, a piston? movable therein v y.

and having a retracted and aV projected position, means for at times moving said piston to itsretracted position, means for at otherv times admitting iuid pressure behindsaidja i piston Ito move it .to-its projected position, a e

plurality of pressure responsive devicesieach responsive to a different pressure Iand connected With said` cylinder atV spaced points f Aalong the cylinder so positionedthat When said piston loccupies its retracted position' noneV of 'said devices 'Willbesubjectedto the j pressure behind said ypiston but that as said piston is moved from its retracted lposition, toward its projected position said devices will Vbecome:subjected tothe pressure behind saidV piston'invthe order of their response toincreasing' pressures, meansffor controlling the pressure of the fluid admitted to said cylinder'behind said'piston'vby a selected one of said devices, `andcar retardingv means ,con-p trolled'by said piston.'`

tures'. l 1 Y .i

HERBERT BONE.

JOIfIN" W. LIVINGSTON.V

ergized for admitting fluid Vpressure in front of said piston to moveit to its retractedpoi sition, a second magnet valve effective when energized for admitting luidpressure behind-saidpiston to move it to its projected position, a third magnet valve for exhausting fluid pressure from in front of said piston or behind said piston according as said thirl valveis deenergized or` energized,"a pressure responsive device connected with said cylinder at such point as to be subjected j to the pressure in front of said piston when the piston is inl its retracted position and to the pressure behind the piston When the piston has been" moved away from itsretracted i position more than a predetermined dis-V tance a normall closed Contact controlled ai Y i by' said pressure responsivevdevice and arranged to become opened if the pressure to vWhich said pressure responsive device is sub-V j jecter exceedsk a predetermined value, a nor-v mallyopen contact controlled by said prescoineclosed itthe pressure tof-Which said pressure responsive device is subjected eX- ceeds a predetermined value which issomewhat higher than the value at which. said normally closed contact becomes opened, means for at times energizing said first magnet valve, means including said normally closed contact for at other times energizing `said second magnet valve, means including said normally open contact for yat still other times sure responsive device and arranged to'be- Y Vil() In testimony Whereofiwe'aiiix our signaino v 

